The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 21, 1978
Filed:
Aug. 19, 1977
August Ferretti, Wilmington, DE (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A process for preparing BaFCl:Eu phosphors of controllable particle size and size distribution is provided. The process comprises (a) preparing an intimate mixture of fine particles of BaFCl, a europium source, preferably water-soluble EuCl.sub.3, and a water-soluble chloride as flux; (b) firing the mixture in an inert atmosphere at a temperature in the range of about 550.degree.-900.degree. C and above the liquid temperature of the flux for a time sufficient to effect reaction and diffusion, and (c) washing the fired product with water to remove the chloride flux. By preselecting the combination of firing temperature and flux concentration in the mixture, phosphor particles of a predetermined size and size distribution can be obtained. This control of the phosphor product is especially advantageous when the intimate mixture is formed in an aqueous medium.